These divisibility rules are quick tests to check whether a number divides evenly by 2 through 12 — without doing the full division.
| Divisible by | Rule |
|---|---|
| 2 | The last digit is even (0, 2, 4, 6, 8) |
| 3 | The sum of the digits is divisible by 3 |
| 4 | The last two digits form a number divisible by 4 |
| 5 | The last digit is 0 or 5 |
| 6 | Divisible by both 2 and 3 |
| 7 | Double the last digit, subtract from the rest; result divisible by 7 |
| 8 | The last three digits are divisible by 8 |
| 9 | The sum of the digits is divisible by 9 |
| 10 | The last digit is 0 |
| 11 | The alternating sum of digits is divisible by 11 |
| 12 | Divisible by both 3 and 4 |
Example
Is 348 divisible by 3? Digit sum = 3 + 4 + 8 = 15, which is divisible by 3 — so yes.